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'Dimethyldioxirane' in keywords
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1999 (1)
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1Author    D. Ietm Ar Kuek, Andreas SchusterRequires cookie*
 Title    Oxidations of Alkylbenzenes with Dimethyldioxirane  
 Abstract    The oxidation o f various alkylbenzenes (1 -1 7) with excess dim ethyldioxirane (D M D O) in hom ogeneous acetone solutions has been studied. In general, the benzylic methylene and methine C -H bonds were oxidized to give the corresponding phenones and tertiary benzylic alcohols, respectively, in relatively low yields. W hereas a tert-buiy\ substituent at the reaction centre leads to very low conversion due to steric hindrance, the presence o f additional phenyl groups appears to favour the oxidation in most, but not all cases. Di-and triphenylmethane (4 and 14) were found to be considerably less reactive than cw-decalin. By contrast, the intra­ molecular competetive oxidation o f isobutylbenzene (19) and l-m ethyl-4-phenylcyclohexanes (20) reveals that the benzylic C -H bonds are slightly more reactive than the tertiary ones at remote positions. 
  Reference    Z. Naturforsch. 46b, 1223—1226 (1991); received April 4 1991 
  Published    1991 
  Keywords    D ioxiranes, Dimethyldioxirane, Alkylbenzenes, Oxidation 
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 TEI-XML for    default:Reihe_B/46/ZNB-1991-46b-1223.pdf 
 Identifier    ZNB-1991-46b-1223 
 Volume    46 
2Author    WolfdieterA. Schenk, Bernhard Steinmetz3, Michael Hagel3, Waldemar Adamb, ChantuR. Saha-MöllerbRequires cookie*
 Title    Oxyfunctionalization of Allyl Thioether Ruthenium Complexes with Dimethyldioxirane [1]  
 Abstract    Allyl thioether complexes [CpRu(P-P)(SRR')lPF6 (P-P = Ph2PCH2PPh2 (dppm), PIitPCtH-iPPI^ (dppe), R = Me, Et, Ph, R' = 3-propenyl, 3-cyclohexenyl, 2-methyl-2-buten-4-yl) and [CpRu(chir)(SRR')]PF6 (chir = (S,S)-Ph2PCHMeCHMePPh2, R = Me, CH2Ph, R' = 2-methyl-2-buten-4-yl) are obtained from the corresponding thiolate complexes by reaction with the appropriate allyl bromide. Careful oxidation with dimethyldioxirane (DMD) gave the allyl sulfoxide complexes [CpRu(P-P)(MeS(0)CH2CH=CH2)]PF6 (P-P = dppm, dppe). Double ox­ idation to the corresponding sulfinylmethyl epoxide complexes can be readily achieved with an excess of DMD. Oxidation of the chir complexes proceeds with only moderate diastereoselectiv-ity. The structure of the (/?, R/S, S) diastereomer of [CpRu(dppm)(MeS(0)CH2CHCH2 0)]PF6 was determined: monoclinic space group P2]/c (No. 14), a = 11.21(2), b = 16.762(9), c = 18.45(4) A, ß = 94.4(1)°, Z = 4. For a representative example, the decomplexation of the sulfoxide-epoxide ligand by sodium iodide in acetone was demonstrated. 
  Reference    Z. Naturforsch. 52b, 1359—1371 (1997); received September 9 1997 
  Published    1997 
  Keywords    Ruthenium Complexes, Sulfoxide, Epoxide, Dimethyldioxirane, Structure 
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 TEI-XML for    default:Reihe_B/52/ZNB-1997-52b-1359.pdf 
 Identifier    ZNB-1997-52b-1359 
 Volume    52 
3Author    Bernhard Steinmetz, Michael Hagel, WolfdieterA. SchenkRequires cookie*
 Title    Synthesis and Oxidation of Ruthenium Allyl Thioether Complexes Bearing Phosphite and Phosphonite Coligands [1]  
 Abstract    Halfsandwich ruthenium thiolate complexes bearing electron-withdrawing phosphite or phos­ phonite ligands were prepared from [CpRu(PPh3)2(SR)l (R = Ph, CH2Ph, Me) and triph-enylphosphite or (5,5')-bis(binaphthylphosphonito)ethane (bbpe), respectively. Reaction with l-bromo-3-methyl-2-butene in the presence of NH4PF6 gave the corresponding allylthioether complexes [CpRu(PR'3)2(S(R)CH2CH=CMe2)]PF6. Treatment with an excess of dimethyl­ dioxirane (DMD) transformed the triphenylphosphite derivatives into diastereomeric (oxiranyl-methyl)sulfoxide complexes with 18 -80% de. NMR monitoring of the reaction revealed that the oxidant attacks the sulfur atom and the C=C double bond with comparable rates. Sim­ ilar oxidation of the bbpe complexes gave mixtures of four diastereoisomers with ratios of (64 : 15 : 1 3 :8) and (51 : 24 : 15 : 10), respectively. 
  Reference    Z. Naturforsch. 54b, 1265—1271 (1999); received July 2 1999 
  Published    1999 
  Keywords    Ruthenium Complexes, Thioether, Sulfoxide, Epoxide, Dimethyldioxirane 
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 TEI-XML for    default:Reihe_B/54/ZNB-1999-54b-1265.pdf 
 Identifier    ZNB-1999-54b-1265 
 Volume    54